I put two bullets in the gun and only have one move. I tell the first bullet to move forward "x" meters. then as seen by gun barrel. Then I tell bullet 1(the one that was shot) to move back to bullet 2(the one still in the gun"

the problem if you do that is that if you have an object that you are shooting it won't know that it was hit. I just tell it to move forward x meters in .01 seconds. I make it go straight forward by telling it to move as seen by gun barrel